Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Beyond annotations, the description discloses two important behaviors: partial updates (unchanged fields retain values) and null-clearing semantics (passing null clears the field). This adds valuable context beyond the idempotentHint and destructiveHint annotations, which do not capture the clearing nuance.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, 18 words, with essential information front-loaded ('Update a CRM deal') and no filler. Every phrase contributes meaning, making it highly concise and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (11 parameters, output schema, annotations), the description covers the critical non-obvious behaviors: partial update and null clearing. The schema documents each parameter, and annotations cover idempotency/safety. While it doesn't mention permissions or return structure, these are not gaps given the rich schema and annotations.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so each parameter already has a description. The description adds collective meaning by stating 'Pass only fields to change' and 'use null to clear,' which explains the overall update pattern and the meaning of null across all nullable parameters, supplementing the schema's per-field 'or null to clear' notes.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Update a CRM deal' with a specific verb and resource, making the tool's purpose clear. It does not explicitly differentiate from sibling tools like update_deal_stage, but the name and scope ('deal' vs 'deal stage') provide adequate distinction.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear usage instructions: 'Pass only fields to change' and 'use null for nullable links/fields to clear them.' However, it does not explicitly mention when to prefer this tool over alternatives (e.g., update_deal_stage) or provide exclusions, leaving usage vs siblings implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.